Quantitative Determination of Some Water-Soluble B Vitamins by Kinetic Analytical Method Based on the Perturbation of an Oscillatory Reaction

Abstract

A novel procedure for kinetic determination of some water-soluble vitamins of the B-group (thiamine (B-1), riboflavin (B-2), niacin (B-3) and pyridoxine (B-6)) by the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory chemical system involving the catalytic decomposition of hydrogen peroxide in the presence of both hydrogen and iodate ions is proposed and validated. The method uses a Pt electrode for potentiometric monitoring of the concentration perturbations of the BL matrix in a stable non-equilibrium stationary state close to the bifurcation point. The proposed method relies on the linear relationship between maximal potential displacements, Delta E-m, caused by the additional known quantities of a B species. Under the optimal established analytical conditions, linear calibration curves were obtained over the range of 0.01-1.0, 0.016-0.128, 5.0-50.0 and 0.05-2.5 mu mol with the limits of detection of 0.01, 0.018, 2.6 and 0.03 mu mol, as well as analytical throughput of 30, 5, 12 and 20 determinations per hour, for B-1, B-2, B-3 and B-6, respectively. The used technical approach also provides simple, effective and convenient method to assay the pharmaceutical formulations containing B-1 together with other active principles such as nicotinamide and vitamin B-12 as well as B-3.